For example, an X-ray imaging apparatus (or an X-ray imaging system) utilizing X-rays output from an X-ray source, and an apparatus (or a system) having a tomosynthesis function utilizing X-rays are widely used, for example, in the medical field. Here, depending on the imaging subject, such as a case in which a human is the subject to be exposed to X-rays, it is desirable to control the region where the subject is exposed to X-rays in order to prevent superfluous radiation exposure.
Under such a situation, techniques are being developed to control the X-ray radiation region of the subject. As a technique to control the X-ray radiation region of the subject, for example, a technique disclosed in Patent Literature 1 below can be given.